Composition and protein digestibility of food supplements containing whey protein

Abstract

Among dietary supplements, those made with whey protein have an excellent amino acid profile and are characterized as proteins of high biological value. However, as a result of lack of uniformity, the nutritional quality of this type of product is uncertain. Thus, this study aimed to verify the protein composition and in vitro digestibility of these products. Twelve samples were obtained. The protein content was determined by the Kjeldahl method. To determine the in vitro protein digestibility,
the percentage of hydrolysis of each sample was measured after treatment with pepsin and pancreatin enzyme sequence. By comparing the protein composition with the declared values on the labels of products it was observed that most of the samples was in accordance with the declared value. Regarding protein digestibility in vitro, great differences were found between the results of the samples. The values founded ranged from 24.2% to 42.2%, which were below the casein hydrolysis of 48.9%. This variation may be due to different protein compositions of food
supplements, since although they show in their main label the term Whey Protein, often contain other proteins, such as soy proteins. In addition, the formulations may have in their composition fruit juices or cocoa. As a conclusion, the study of the actual protein content, as compared to the one declared on the label, and even the degree of hydrolysis of these formulations, as indicative of their digestibilities, is increasingly important.